This invention relates to hydraulic cylinder assemblies and more particularly to a method of forming a hydraulic cylinder assembly.
Hydraulic cylinder assemblies are in common usage. The typical assembly includes a cylindrical main body member and a piston assembly disposed within the central bore of the cylindrical main body member. Pressurized hydraulic fluid is discharged from the cylindrical main body member in response to stroking reciprocal movement of the piston assembly within the bore of the cylindrical main body. Hydraulic cylinder assemblies were originally formed primarily of metallic materials but more recently attempts have been made to form at least the cylindrical main body of the assembly out of a plastic material so as to facilitate the manufacturing process and reduce the cost of the assembly. Forming the main body cylindrical member out of plastic, while reducing cost, has the disadvantage of creating sink marks along the bore of the cylinder adjacent the locations where appendages, such as mounting flanges and reservoirs, are provided exteriorally of the cylinder body. The sink marks interfere with effective sealing as between the elastomeric seals carried by the piston assembly and the bore of the cylinder and further introduce a rocking or wobbling potential with respect to the piston assembly with resultant excessive wear of the piston assembly.